Flow Diversion vs. Coiling for Large and Giant Intracranial Aneurysms: A Systematic Review and Meta-Analysis

Background: The management of large (≥10 mm) and giant (≥25 mm) intracranial aneurysms remains clinically challenging due to their elevated rupture risk, morbidity, and procedural complications, which pose a dilemma for both intervention and conservative management. Flow diversion (FD) has emerged as a promising endovascular approach, although its comparative safety and efficacy versus Coiling remain unclear. Methods: Following PRISMA guidelines, studies published between January 2000 and March 2025 were identified across PubMed, EMBASE, Scopus, and Web of Science. Outcomes assessed included aneurysm recurrence, complete occlusion, favorable clinical outcomes, procedure-related complications and mortality. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated, and heterogeneity and publication bias were assessed. Results: A total of 1893 patients (1256 FD, 637 Coiling) and 1915 aneurysms across 33 studies were included. FD significantly reduced recurrence compared to Coiling (8% vs. 27%; p = 0.0001) and showed a trend toward a higher rate of complete occlusion (p = 0.0571). However, FD had a modestly increased rate of hemorrhagic complications (p = 0.0495). No other significant differences were found in clinical outcomes, major complications, ischemic events, delayed rupture, or mortality. Conclusions: Both FD and Coiling are effective and generally safe for large and giant intracranial aneurysms. FD is associated with lower recurrence and a trend toward a higher rate of complete occlusion, with similar overall safety but slightly higher hemorrhagic risk. FD is emerging as a preferred first-line option for large and giant unruptured aneurysms, while coiling remains important for ruptured aneurysms or when anatomical constraints limit the use of FD.